Table 1. Characteristics of blood transfusion episodes.
| Exposure category (storage age of transfused red-cell concentrates) | |||||
|---|---|---|---|---|---|
| 0-9 days | 10-19 days | 20-29 days | 30-42 days | Mixed age | |
| No. transfusion episodes available for analysis at day 1 (% of total) | 103,402 (25.5%) | 140,619 (34.7%) | 63,729 (15.7%) | 32,855 (8.1%) | 64,354 (15.9%) |
| No. transfusion episodes available for analysis at day 7 (% of total)* | 83,828 (22.0%) | 113,953 (29.9%) | 49,845 (13.1%) | 25,897 (6.8%) | 107,026 (28.1%) |
| Median storage time (IQR) | 7 (5-8) | 14 (12-16) | 23 (21-26) | 34 (31-37) | 17 (11-22) |
| Female sex, No. (% of category) | 58,142 (56.2%) | 79,285 (56.4%) | 35,561 (55.8%) | 18,608 (56.6%) | 34,101 (53.0%) |
| Swedish, No. (% of category) | 87,412 (84.5%) | 113,720 (80.9%) | 51,899 (81.4%) | 28,507 (86.8%) | 55,722 (86.6%) |
| Patient age, median (IQR) | 71.7 (57.8-79.6) | 72.3 (59.1-80.1) | 72.6 (60.3-80.2) | 73.2 (61.1-80.6) | 71.6 (58.0-79.3) |
| Number of transfusions on day 1, No. (% of category) | |||||
| 1-5 | 96,536 (93.4%) | 133,195 (94.7%) | 61,035 (95.8%) | 31,677 (96.4%) | 49,897 (77.5%) |
| 6-10 | 4,793 (4.6%) | 5,476 (3.9%) | 2,108 (3.3%) | 957 (2.9%) | 8,315 (12.9%) |
| >10 | 2,073 (2.0%) | 1,948 (1.4%) | 586 (0.9%) | 221 (0.7%) | 6,142 (9.5%) |
| Median number (IQR) | 2 (2-2) | 2 (2-2) | 2 (1-2) | 2 (1-2) | 3 (2-5) |
| Number of transfusions on day 1-7, No. (% of category)† | |||||
| 1-5 | 74,585 (89.0%) | 103,590 (90.9%) | 46,302 (92.9%) | 24,097 (93.0%) | 69,847 (65.3%) |
| 6-10 | 6,265 (7.5%) | 7,385 (6.5%) | 2,646 (5.3%) | 1,366 (5.3%) | 21,758 (20.3%) |
| >10 | 2,978 (3.6%) | 2,978 (2.6%) | 897 (1.8%) | 434 (1.7%) | 15,421 (14.4%) |
| Median number (IQR) | 2 (2-4) | 2 (2-3) | 2 (2-3) | 2 (2-3) | 4 (3-7) |
| Median length of hospital stay (IQR)** | 13 (7-26) | 12 (7-27) | 12 (7-25) | 12 (7-23) | 13 (7-26) |
| Blood group, No. (% of category) | |||||
| A | 56,928 (55.1%) | 67,772 (48.2%) | 25,854 (40.6%) | 9,828 (29.9%) | 26,178 (40.7%) |
| AB | 2,444 (2.4%) | 2,979 (2.1%) | 3,163 (5.0%) | 4,536 (13.8%) | 4,234 (6.6%) |
| B | 8,807 (8.5%) | 10,114 (7.2%) | 7,161 (11.2%) | 5,643 (17.2%) | 8,279 (12.9%) |
| O | 35,223 (34.1%) | 59,754 (42.5%) | 27,551 (43.2%) | 12,848 (39.1%) | 25,663 (39.9%) |
| Indication for transfusion, No. (% of category) | |||||
| 1. Trauma | 14,065 (13.6%) | 21,654 (15.4%) | 9,400 (14.7%) | 5,344 (16.3%) | 9,090 (14.1%) |
| 2. Non-trauma, CVD surgery | 12,895 (12.5%) | 15,980 (11.4%) | 7,465 (11.7%) | 3,657 (11.1%) | 9,196 (14.3%) |
| 3. Non-trauma, non-CVD surgery for malignant disease | 9,677 (9.4%) | 13,247 (9.4%) | 6,624 (10.4%) | 3,285 (10.0%) | 7,166 (11.1%) |
| 4. Non-trauma, non-CVD, non-malignant surgery | 22,387 (21.7%) | 32,136 (22.9%) | 15,226 (23.9%) | 7,402 (22.5%) | 14,897 (23.1%) |
| 5. Non-trauma, non-surgery, hematologic malignancy | 3,893 (3.8%) | 3,338 (2.4%) | 1,238 (1.9%) | 645 (2.0%) | 1,412 (2.2%) |
| 6. Other indication | 40,485 (39.2%) | 54,264 (38.6%) | 23,776 (37.3%) | 12,522 (38.1%) | 22,593 (35.1%) |
IQR denotes interquartile range; CVD denotes cardiovascular disease.
*
The number of patients available for analysis at day 7 decreased in all but the Mixed category due to deaths occurring during the first 7 days and due to patients receiving units of another exposure category, non-identical units or autologous units on days 2-7.
†
Considering only patients available for analysis on day 8.
**
During first 30 days following transfusion.